100-200mA Variable constant current LED Driver

Hello Guys.

Are there any ways where we can implement a 30V,100-200mA Constant current power supply.

with the help of topswicth/Linkshwitch or Lytswitch.


Or does anyone having idea with the help of Power Integration tools

Input voltage:120-275VAC
Output Voltage:30V
Ouptut current:100-200mA (vARIABLE BY POT)

I would like to understand the same article or Weblinks
Regards
Marx

This could be your constant current. I have placed the load in the collector in order to ease the output voltage of the OP Amp.

You need a SMPS for the 30 V. Depending on your exact application, probably the load can be placed in the emitter and derive the supply of the OP from the VCC (SMPS).

Depending on the intended variation of the current, the reference voltage can be derived from the SMPS or bypassed with additional linear voltage regulator for lower ripple.

For the SMPS for 30 V output and 200mA, I would go with Flyback, so check how power integrations implements a Flyback with those requirements.

P.D.: I guessed from your very little information that you want to drive a LED string in series with the 30 V, so that explains the 28 V voltage source which represents the large string of LEDs.

One way to do that with Linkswitch would be to use an opamp to provide the feedback voltage. If you don't want it adjustable you can remove the opamp altogether and just select Rsns appropriately and connect D2 from the top of Rsns directly to the FB node. With the opamp I haven't tested it but you have to check and see if it causes any stability problems. You can get help from the application support from Power Integrations.